Truss connector knob
Registration flats
Upper truss support ring
Truss connector
Figure 27. When the knob in the truss connector is tightened, it will clamp the truss connector against the registration flats on the upper truss support ring.
Altitude side bearing
Altitude tensioning metal washer
Altitude tensioning
Teflon washer
Altitude tensioning knob
IntelliScope port
Figure 28. Lift the optical tube by grasping two truss poles and carefully lower it so that the large altitude bearing hubs rest on the altitude bearing cylinders on the side panels.
to the truss connectors (see Figure 26). This should rare- ly need to be done.
The telescope is now assembled and ready to be placed into the Dobsonian base.
Mounting the Optical Tube on the
Dobsonian Base
1.Grasp two opposing truss poles as shown in Figure 28 and lift the optical tube, then gently place it into the Dobsonian base so the altitude bearings on either side of
Figure 29. Insert the shaft of the altitude tensioning knob, with metal and Teflon washers attached, into the side of the base with the IntelliScope port, and thread it into the tube’s altitude side bearing.
the tube rest on the base’s bearing cylinders. Be careful when doing this, as the optical tube is somewhat heavy and unwieldy. Orient the optical tube on the base as seen in Figure 1. Make certain the optical tube does not get hung up on the vertical stop or the CorrecTension pads (i.e. the three square white pads on the inside surface of the left side panel) as you put it in place. Also, be very careful not to hit the altitude encoder with the side bear- ing on the tube when doing this or damage to the encod- er could result. The bumper is positioned to help prevent such contact. Once on the bearing cylinders, the tube should pivot freely up and down with gentle hand pres- sure. Note that the tube will not yet be properly balanced, since the eyepiece and finder scope are not in place, and the altitude tensioning knob has not been installed.
2.Select one of the altitude tensioning/retaining knobs (they are the same) and slide the tensioning knob metal washer onto the shaft, followed by the tensioning knob white Teflon washer (you will need to thread the Teflon washer onto the shaft, this keeps both washers captive on the knob’s shaft). These parts are found in the box with the Dobsonian base. Push the shaft of the knob through the hole in the side panel that has the IntelliScope port (Figure 29). Thread the knob into the optical tube’s alti- tude bearing until the knob pulls the altitude bearing against the CorrecTension pads on the interior surface of the left panel.
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